Evolutionary histories of breast cancer and related clones.

Recent studies have documented frequent evolution of clones carrying common cancer mutations in apparently normal tissues, which are implicated in cancer development1-3. However, our knowledge is still missing with regard to what additional driver events take place in what order, before one or more of these clones in normal tissues ultimately evolve to cancer. Here, using phylogenetic analyses of multiple microdissected samples from both cancer and non-cancer lesions, we show unique evolutionary histories of breast cancers harbouring der(1;16), a common driver alteration found in roughly 20% of breast cancers. The approximate timing of early evolutionary events was estimated from the mutation rate measured in normal epithelial cells. In der(1;16)(+) cancers, the derivative chromosome was acquired from early puberty to late adolescence, followed by the emergence of a common ancestor by the patient's early 30s, from which both cancer and non-cancer clones evolved. Replacing the pre-existing mammary epithelium in the following years, these clones occupied a large area within the premenopausal breast tissues by the time of cancer diagnosis. Evolution of multiple independent cancer founders from the non-cancer ancestors was common, contributing to intratumour heterogeneity. The number of driver events did not correlate with histology, suggesting the role of local microenvironments and/or epigenetic driver events. A similar evolutionary pattern was also observed in another case evolving from an AKT1-mutated founder. Taken together, our findings provide new insight into how breast cancer evolves.

Capivasertib in Hormone Receptor-Positive Advanced Breast Cancer.

BACKGROUND: AKT pathway activation is implicated in endocrine-therapy resistance. Data on the efficacy and safety of the AKT inhibitor capivasertib, as an addition to fulvestrant therapy, in patients with hormone receptor-positive advanced breast cancer are limited. METHODS: In a phase 3, randomized, double-blind trial, we enrolled eligible pre-, peri-, and postmenopausal women and men with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer who had had a relapse or disease progression during or after treatment with an aromatase inhibitor, with or without previous cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor therapy. Patients were randomly assigned in a 1:1 ratio to receive capivasertib plus fulvestrant or placebo plus fulvestrant. The dual primary end point was investigator-assessed progression-free survival assessed both in the overall population and among patients with AKT pathway-altered (PIK3CA, AKT1, or PTEN) tumors. Safety was assessed. RESULTS: Overall, 708 patients underwent randomization; 289 patients (40.8%) had AKT pathway alterations, and 489 (69.1%) had received a CDK4/6 inhibitor previously for advanced breast cancer. In the overall population, the median progression-free survival was 7.2 months in the capivasertib-fulvestrant group, as compared with 3.6 months in the placebo-fulvestrant group (hazard ratio for progression or death, 0.60; 95% confidence interval [CI], 0.51 to 0.71; P<0.001). In the AKT pathway-altered population, the median progression-free survival was 7.3 months in the capivasertib-fulvestrant group, as compared with 3.1 months in the placebo-fulvestrant group (hazard ratio, 0.50; 95% CI, 0.38 to 0.65; P<0.001). The most frequent adverse events of grade 3 or higher in patients receiving capivasertib-fulvestrant were rash (in 12.1% of patients, vs. in 0.3% of those receiving placebo-fulvestrant) and diarrhea (in 9.3% vs. 0.3%). Adverse events leading to discontinuation were reported in 13.0% of the patients receiving capivasertib and in 2.3% of those receiving placebo. CONCLUSIONS: Capivasertib-fulvestrant therapy resulted in significantly longer progression-free survival than treatment with fulvestrant alone among patients with hormone receptor-positive advanced breast cancer whose disease had progressed during or after previous aromatase inhibitor therapy with or without a CDK4/6 inhibitor. (Funded by AstraZeneca and the National Cancer Institute; CAPItello-291 ClinicalTrials.gov number, NCT04305496.).

Mechanisms of sensitivity and resistance to CDK4/CDK6 inhibitors in hormone receptor-positive breast cancer treatment.

Cell cycle dysregulation is a hallmark of cancer that promotes eccessive cell division. Cyclin-dependent kinase 4 (CDK4) and cyclin-dependent kinase 6 (CDK6) are key molecules in the G1-to-S phase cell cycle transition and are crucial for the onset, survival, and progression of breast cancer (BC). Small-molecule CDK4/CDK6 inhibitors (CDK4/6i) block phosphorylation of tumor suppressor Rb and thus restrain susceptible BC cells in G1 phase. Three CDK4/6i are approved for the first-line treatment of patients with advanced/metastatic hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) BC in combination with endocrine therapy (ET). Though this has improved the clinical outcomes for survival of BC patients, there is no established standard next-line treatment to tackle drug resistance. Recent studies suggest that CDK4/6i can modulate other distinct effects in both BC and breast stromal compartments, which may provide new insights into aspects of their clinical activity. This review describes the biochemistry of the CDK4/6-Rb-E2F pathway in HR+ BC, then discusses how CDK4/6i can trigger other effects in BC/breast stromal compartments, and finally outlines the mechanisms of CDK4/6i resistance that have emerged in recent preclinical studies and clinical cohorts, emphasizing the impact of these findings on novel therapeutic opportunities in BC.

Non-surgical ablation for breast cancer: an emerging therapeutic option.

Non-surgical ablation is emerging as an alternative local therapy option for patients with early-stage breast cancer and encompasses two main types of percutaneous therapeutic procedures: radiofrequency ablation and cryoablation. Both techniques involve obliteration of a spherical lesion and feasibility studies have shown that complete tumour ablation is achievable with good or excellent cosmetic results. Although few clinical studies have directly compared non-surgical ablation with conventional surgical resection, observational studies indicate that clinical outcomes are favourable with acceptable rates of local control and no detriment to long-term survival. There remain outstanding issues with these percutaneous ablative techniques that require resolution before they could be incorporated into routine clinical practice. Hence, a consensus meeting was convened to discuss the challenges of non-surgical ablation and clarify indications for its use alongside clinical management pathways. In this Policy Review we will address some of the broader biological aspects of non-surgical ablation, including immune-modulatory effects and potential novel applications for the future.

Time-series blood cytokine profiles correlate with treatment responses in triple-negative breast cancer patients.

BACKGROUND: Triple-negative breast cancer (TNBC) is the most heterogeneous breast cancer subtype. Partly due to its heterogeneity, it is currently challenging to stratify TNBC patients and predict treatment outcomes. METHODS: In this study, we examined blood cytokine profiles of TNBC patients throughout treatments (pre-treatment, during chemotherapy, pre-surgery, and 1 year after the surgery in a total of 294 samples). We analyzed the obtained cytokine datasets using weighted correlation network analyses, protein-protein interaction analyses, and logistic regression analyses. RESULTS: We identified five cytokines that correlate with good clinical outcomes: interleukin (IL)-1α, TNF-related apoptosis-inducing ligand (TRAIL), Stem Cell Factor (SCF), Chemokine ligand 5 (CCL5 also known as RANTES), and IL-16. The expression of these cytokines was decreased during chemotherapy and then restored after the treatment. Importantly, patients with good clinical outcomes had constitutively high expression of these cytokines during treatments. Protein-protein interaction analyses implicated that these five cytokines promote an immune response. Logistic regression analyses revealed that IL-1α and TRAIL expression levels at pre-treatment could predict treatment outcomes in our cohort. CONCLUSION: We concluded that time-series cytokine profiles in breast cancer patients may be useful for understanding immune cell activity during treatment and for predicting treatment outcomes, supporting precision medicine. TRIAL REGISTRATION: The study has been registered with the University Hospital Medical Information Network Clinical Trials Registry ( http://www.umin.ac.jp/ctr/index-j.htm ) with the unique trial number UMIN000023162. The association Japan Breast Cancer Research Group trial number is JBCRG-22. The clinical outcome of the JBCRG-22 study was published in Breast Cancer Research and Treatment on 25 March 2021. https://doi.org/10.1007/s10549-021-06184-w .

Association of Neutrophil-to-Lymphocyte Ratio and Absolute Lymphocyte Count With Clinical Outcomes in Advanced Breast Cancer in the MONARCH 2 Trial.

BACKGROUND: Established prognostic factors for treatment response to cyclin-dependent kinases 4 and 6 inhibitors are currently lacking. We aimed to investigate the relationship of pretreatment neutrophil-to-lymphocyte ratio (NLR) and absolute lymphocyte count (ALC) to abemaciclib outcomes. PATIENTS AND METHODS: This was a post hoc analysis of data from MONARCH 2, a phase III study of abemaciclib or placebo plus fulvestrant in hormone-receptor positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer that progressed on endocrine therapy. Patients were divided into high and low categories based on baseline NLR (cutoff: 2.5) and ALC (cutoff: 1.5 × 109/L). The association of baseline NLR and ALC with progression-free survival (PFS) and overall survival (OS) was explored using Cox models and Kaplan-Meier estimates. Tumor response and safety were also examined. RESULTS: NLR and ALC data were available for 645 patients (abemaciclib: N = 426; placebo: N = 219). Low-baseline NLR or high-baseline ALC was consistently associated with positive PFS and OS trends; low-baseline NLR subgroups also showed trends for better response. The abemaciclib treatment effect against placebo was observed regardless of baseline NLR or ALC. Univariate analyses showed baseline NLR and ALC were prognostic of PFS and OS. Baseline NLR remained significant in the multivariate model (P < .0001). No unexpected differences in safety were observed by baseline NLR or ALC. CONCLUSION: Baseline NLR was independently prognostic of PFS and OS. Low-baseline NLR was associated with numerically better efficacy outcomes, but the benefit of adding abemaciclib to fulvestrant was similar irrespective of baseline NLR status.

Long-term outcomes of neoadjuvant trastuzumab emtansine + pertuzumab (T-DM1 + P) and docetaxel + carboplatin + trastuzumab + pertuzumab (TCbHP) for HER2-positive primary breast cancer: results of the randomized phase 2 JBCRG20 study (Neo-peaks).

PURPOSE: The randomized phase 2 Neo-peaks study examined usefulness of neoadjuvant trastuzumab emtansine + pertuzumab (T-DM1 + P) following docetaxel + carboplatin + trastuzumab + pertuzumab (TCbHP) as compared with the standard TCbHP regimen. We previously reported that pCR rate after neoadjuvant therapy tended to be higher with TCbHP followed by T-DM1 + P. We conducted an exploratory analysis of prognosis 5 years after surgery. METHODS: Neoadjuvant treatment with TCbHP (6 cycles; group A), TCbHP (4 cycles) followed by T-DM1 + P (4 cycles; group B), and T-DM1 + P (4 cycles; group C, + 2 cycles in responders) were compared. Group C non-responders after 4 cycles were switched to an anthracycline-based regimen. We evaluated 5-year disease-free survival (DFS), distant DFS (DDFS), and overall survival (OS). RESULTS: Data from 203 patients (50, 52, and 101 in groups A-C, respectively) were analyzed. No significant intergroup differences were found for DFS, DDFS, or OS. The 5-year DFS rates (95% CI) were 91.8% (79.6-96.8%), 92.3% (80.8-97.0%), and 88.0% (79.9-93.0%) in groups A-C, respectively. TCbHP followed by T-DM1 + P and T-DM1 + P with response-guided addition of anthracycline therapy resulted in similar long-term prognosis to that of TCbHP. CONCLUSIONS: In patients who achieved pCR after neoadjuvant therapy with T-DM1 + P, omission of adjuvant anthracycline may be considered, whereas treatment should be adjusted for non-pCR patients with residual disease. T-DM1 + P with response-guided treatment adjustment may be useful for minimizing toxicity. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: UMIN-CTR, UMIN000014649, prospectively registered July 25, 2014. Some of the study results were presented as a Mini Oral session at the ESMO Breast Cancer 2023 (Berlin, Germany, 11-13 May 2023).

Comparison of cisplatin-based versus standard preoperative chemotherapy in patients with operable triple-negative breast cancer: propensity score matching and inverse probability of treatment weighting analysis.

PURPOSE: The efficacy of carboplatin is non-equivalent to that of cisplatin (CDDP) for various tumor types in curative settings. However, the role of CDDP in operable triple-negative breast cancer (TNBC) patients remains unknown. We conducted a multicenter observational study to examine the effects of CDDP added to preoperative chemotherapy in patients with TNBC. METHODS: This retrospective study consecutively included previously untreated patients with stage I-III TNBC treated with preoperative chemotherapy with or without CDDP. The primary endpoint was distant disease-free survival (DDFS). Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to minimize confounding biases in comparisons between the two groups. RESULTS: A total of 138 patients were enrolled in the study. Of these, 52 were in the CDDP group and 86 in the non-CDDP group. DDFS was significantly better in the CDDP group than in the non-CDDP group (unadjusted hazard ratio (HR) 0.127 and p < 0.001, PSM HR 0.141 and p < 0.003, IPTW HR 0.123 and p = < 0.001). Furthermore, among the patients with residual cancer burden (RCB) class II/III, DDFS was better in the CDDP group than in the non-CDDP group (unadjusted HR 0.192 and p = 0.013, PSM HR 0.237 and p = 0.051, IPTW HR 0.124 and p = 0.059). CONCLUSION: Our study showed that CDDP-containing regimens achieved favorable prognoses in patients with operable TNBC, especially for the RCB class II/III population. Confirmative studies are warranted to elucidate the role of CDDP in TNBC treatment.

Quantitative analysis of the effect of docetaxel-induced edema on quality of life in patients with breast cancer and related factors: a prospective cohort study.

BACKGROUND: Systemic edema is an adverse effect of docetaxel chemotherapy and causes distress to patients, including those receiving this agent for breast cancer. However, its characteristics and factors related to its effect on quality of life (QoL) have not been adequately investigated. In this study, we assessed systemic edema quantitatively, explored related factors, and evaluated QoL in patients receiving docetaxel for breast cancer. METHODS: The study had a prospective cohort design and included 37 patients with no known history of swelling who were treated with docetaxel between September 2019 and April 2022. Patients were examined at the start, middle, and end of their course of treatment and 1 and 2 months later. Body water content, body mass, fat mass, and muscle mass were quantified using bioelectrical impedance analysis. Systemic edema was evaluated with reference to the Common Terminology Criteria for Adverse Events. The timing of development of systemic edema at any anatomical site that was grade 2 or worse was recorded. QoL was assessed using the Quality of Life-Anti Cancer Drug scale. Nutrition was evaluated using the Brief-type self-administered diet history questionnaire. Multivariable logistic regression analysis was performed to identify related factors. QoL was also compared between patients with edema and those without edema. RESULTS: Systemic edema developed in 67% of the study participants and was most prevalent at the end of treatment. Body fat mass (adjusted odds ratio [aOR] 0.802, 95% confidence interval [CI] 0.651-0.988, p = 0.038), disease stage (aOR 3.279, 95% CI 0.493-21.793, p = 0.219), and history of alcohol consumption (aOR 0.141, 95% CI 0.013-1.521, p = 0.106) were identified as risk factors for docetaxel-induced edema. Participants who developed systemic edema experienced more physical, vital, and emotional distress 1 month after treatment than those who did not. There was no association between systemic edema and nutrition. CONCLUSIONS: Systemic edema may develop after treatment with docetaxel and increase distress in patients with a high body fat mass. Patients at risk of systemic edema should be informed in advance about the potential frequency, location, and timing of its onset and encouraged to self-manage this condition.

Impact of the coronavirus disease 2019 pandemic on 20 representative surgical procedures in Japan based on the National Clinical Database: annual surveillance of 2021 by the Japan Surgical Society.

PURPOSE: The volume of surgical services has significantly reduced globally due to the coronavirus disease 2019 (COVID-19) pandemic. This study evaluated the level of recovery in terms of the number of operations performed in Japan in 2021, based on nationwide periodic surveillance. METHODS: Information on the weekly and annual volumes of 20 representative procedures in 6 surgical subspecialties in 2021 was extracted from the National Clinical Database. Statistical data for 2018 and 2019 (pre-pandemic era) were compared with those for 2020. Data on waves of infection, peak period, and high-prevalence areas (13 of 47 prefectures) were analyzed individually. RESULTS: The volumes of the 10 procedures, including gastrectomy, hepatectomy, valve replacement and valve plasty, coronary artery bypass grafting, infrarenal abdominal aorta replacement, ventricular septal defect closure, lung lobectomy, inguinal hernia repair (age < 16 years old), and appendectomy (age < 16 years old), did not reach 95% of that in the pre-pandemic era. The most striking decline in the surgical volume of these 10 procedures was observed during the peak period of wave 5 in high-prevalence areas. CONCLUSION: This near-complete enumeration survey identified the polarization of 20 representative procedures in terms of resumption of surgical service after the pandemic.

Abemaciclib plus endocrine therapy for hormone receptor-positive, HER2-negative, node-positive, high-risk early breast cancer (monarchE): results from a preplanned interim analysis of a randomised, open-label, phase 3 trial.

BACKGROUND: Adjuvant abemaciclib plus endocrine therapy previously showed a significant improvement in invasive disease-free survival and distant relapse-free survival in hormone receptor-positive, human epidermal growth factor receptor 2 (HER2; also known as ERBB2)-negative, node-positive, high-risk, early breast cancer. Here, we report updated results from an interim analysis to assess overall survival as well as invasive disease-free survival and distant relapse-free survival with additional follow-up. METHODS: In monarchE, an open-label, randomised, phase 3 trial, adult patients (aged ≥18 years) who had hormone receptor-positive, HER2-negative, node-positive, early breast cancer at a high risk of recurrence with an Eastern Cooperative Oncology Group performance status of 0 or 1 were recruited from 603 sites including hospitals and academic and community centres in 38 countries. Patients were randomly assigned (1:1) by means of an interactive web-based response system (block size of 4), stratified by previous chemotherapy, menopausal status, and region, to receive standard-of-care endocrine therapy of physician's choice for up to 10 years with or without abemaciclib 150 mg orally twice a day for 2 years (treatment period). All therapies were administered in an open-label manner without masking. High-risk disease was defined as either four or more positive axillary lymph nodes, or between one and three positive axillary lymph nodes and either grade 3 disease or tumour size of 5 cm or larger (cohort 1). A smaller group of patients were enrolled with between one and three positive axillary lymph nodes and Ki-67 of at least 20% as an additional risk feature (cohort 2). This was a prespecified overall survival interim analysis planned to occur 2 years after the primary outcome analysis for invasive disease-free survival. Efficacy was assessed in the intention-to-treat population. Safety was assessed in all treated patients. The study is registered with ClinicalTrials.gov, NCT03155997, and is ongoing. FINDINGS: Between July 17, 2017, and Aug 12, 2019, 5637 patients were randomly assigned (5601 [99·4%] were women and 36 [0·6%] were men). 2808 were assigned to receive abemaciclib plus endocrine therapy and 2829 were assigned to receive endocrine therapy alone. At a median follow-up of 42 months (IQR 37-47), median invasive disease-free survival was not reached in either group and the invasive disease-free survival benefit previously reported was sustained: HR 0·664 (95% CI 0·578-0·762, nominal p<0·0001). At 4 years, the absolute difference in invasive disease-free survival between the groups was 6·4% (85·8% [95% CI 84·2-87·3] in the abemaciclib plus endocrine therapy group vs 79·4% [77·5-81·1] in the endocrine therapy alone group). 157 (5·6%) of 2808 patients in the abemaciclib plus endocrine therapy group died compared with 173 (6·1%) of 2829 patients in the endocrine therapy alone group (HR 0·929, 95% CI 0·748-1·153; p=0·50). The most common grade 3-4 adverse events were neutropenia (in 548 [19·6%] of 2791 patients receiving abemaciclib plus endocrine therapy vs 24 [0·9%] of 2800 patients in the endocrine therapy alone group), leukopenia (318 [11·4%] vs 11 [0·4%]), and diarrhoea (218 [7·8%] vs six [0·2%]). Serious adverse events occurred in 433 (15·5%) of 2791 patients receiving abemaciclib plus endocrine therapy versus 256 (9·1%) of 2800 receiving endocrine therapy. There were two treatment-related deaths in the abemaciclib plus endocrine therapy group (diarrhoea and pneumonitis) and none in the endocrine therapy alone group. INTERPRETATION: Adjuvant abemaciclib reduces the risk of recurrence. The benefit is sustained beyond the completion of treatment with an absolute increase at 4 years, further supporting the use of abemaciclib in patients with high-risk hormone receptor-positive, HER2-negative early breast cancer. Further follow-up is needed to establish whether overall survival can be improved with abemaciclib plus endocrine therapy in these patients. FUNDING: Eli Lilly.

Oncobiology and treatment of breast cancer in young women.

Female breast cancer emerged as the leading cancer type in terms of incidence globally in 2020. Although mortality due to breast cancer has improved during the past three decades in many countries, this trend has reversed in women less than 40 years since the past decade. From the biological standpoint, there is consensus among experts regarding the clinically relevant definition of breast cancer in young women (BCYW), with an age cut-off of 40 years. The idea that breast cancer is an aging disease has apparently broken in the case of BCYW due to the young onset and an overall poor outcome of BCYW patients. In general, younger patients exhibit a worse prognosis than older pre- and postmenopausal patients due to the aggressive nature of cancer subtypes, a high percentage of cases with advanced stages at diagnosis, and a high risk of relapse and death in younger patients. Because of clinically and biologically unique features of BCYW, it is suspected to represent a distinct biologic entity. It is unclear why BCYW is more aggressive and has an inferior prognosis with factors that contribute to increased incidence. However, unique developmental features, adiposity and immune components of the mammary gland, hormonal interplay and crosstalk with growth factors, and a host of intrinsic and extrinsic risk factors and cellular regulatory interactions are considered to be the major contributing factors. In the present article, we discuss the status of BCYW oncobiology, therapeutic interventions and considerations, current limitations in fully understanding the basis and underlying cause(s) of BCYW, understudied areas of BCYW research, and postulated advances in the coming years for the field.

Abemaciclib plus fulvestrant in East Asian women with HR+, HER2- advanced breast cancer: Overall survival from MONARCH 2.

MONARCH 2 is a global, randomized, double-blind, phase 3 study of abemaciclib/placebo + fulvestrant in patients with hormone receptor positive, human epidermal growth factor receptor 2-negative advanced breast cancer. The East Asian population comprised 212 (31.7%) of the 669 intent-to-treat population in the MONARCH 2 trial. Consistent with the primary analysis, this subpopulation analysis of East Asian patients indicated progression-free survival benefit in the abemaciclib arm. The median overall survival was not reached in the abemaciclib arm and was 48.9 months in the placebo arm (hazard ratio 0.80; 95% confidence interval 0.52-1.24; p = 0.377). In addition, other efficacy endpoints, including time to chemotherapy, chemotherapy free survival, and time to second disease progression, indicated benefit in the abemaciclib arm. This analysis found no new safety concerns with longer follow-up. These findings support the positive benefit-risk balance of the MONARCH 2 regimen in East Asian patients with hormone receptor positive, human epidermal growth factor receptor 2-negative advanced breast cancer.

Discovery of lipid profiles in plasma-derived extracellular vesicles as biomarkers for breast cancer diagnosis.

Lipids are a major component of extracellular vesicles; however, their significance in tumorigenesis and progression has not been well elucidated. As we previously found that lipid profiles drastically changed in breast tumors upon progression, we hypothesized that lipid profiles of plasma-derived extracellular vesicles could be utilized as breast cancer biomarkers. Here, we adopted modified sucrose cushion ultracentrifugation to isolate plasma-derived extracellular vesicles from breast cancer (n = 105), benign (n = 11), and healthy individuals (n = 43) in two independent cohorts (n = 126 and n = 33) and conducted targeted lipidomic analysis. We established a breast cancer diagnostic model comprising three lipids that showed favorable performance with the area under the receiver operating characteristic curve of 0.759, 0.743, and 0.804 in the training, internal validation, and external test sets, respectively. Moreover, we identified several lipids that could effectively discriminate breast cancer progression and subtypes: phosphatidylethanolamines and phosphatidylserines were relatively higher in Stage III, whereas phosphatidylcholines and sphingomyelins were higher in Stage IV; phosphatidylcholines and ceramides were correspondingly concentrated in HER2-positive patients, while lysophosphatidylcholines and polyunsaturated triglycerides were concentrated in the triple-negative breast cancer subtype. Lipid profiling of plasma-derived extracellular vesicles is a non-invasive and promising approach for diagnosing, staging, and subtyping breast cancer.

Adjuvant Abemaciclib Combined with Endocrine Therapy: Efficacy Results in monarchE Cohort 1.

The monarchE Cohort 1 patient population was enrolled based on high-risk clinicopathological features that can easily be identified as part of routine clinical breast cancer evaluation. Efficacy data from Cohort 1 demonstrate substantial evidence of benefit for adjuvant abemaciclib+ET in patients with HR+, HER2- early breast cancer at high risk of recurrence (ClinicalTrials.gov: NCT03155997 [monarchE]).

Analysis of prognosis in different subtypes of invasive lobular carcinoma using the Japanese National Cancer Database-Breast Cancer Registry.

PURPOSE: Many studies have shown that the prognosis of invasive lobular carcinoma (ILC) is better than that of invasive ductal carcinoma (IDC). However, both disorders exhibit different prognoses according to molecular subtype, and the prognosis of ILC subtypes might depend on their hormone receptor positivity rate. This study clarified the prognosis of ILC and IDC in each subtype and examined the effectiveness of adjuvant chemotherapy (CT) in luminal ILC. METHODS: We planned the analysis using data from the Breast Cancer Registry in Japan. Because it was presumed that there are differences in characteristics between ILC and IDC, we created matched cohorts using exact matching to compare their prognoses. We compared the prognosis of ILC and IDC for each subtype. We also compared the prognosis of luminal ILC between the CT and non-CT groups. RESULTS: For all subtypes, the disease-free survival (DFS) and overall survival (OS) of ILC were poorer than those of IDC. In the analysis by each subtype, no statistically significant difference was found in DFS and OS in luminal human epidermal growth factor 2 (HER2), HER2, and triple-negative cohorts; however, luminal ILC had significantly poorer DFS and OS than luminal IDC. The CT effects on the prognosis of luminal ILC were greater in more advanced cases. CONCLUSION: Luminal ILC had a poorer prognosis than luminal IDC, contributing to the worse prognosis of ILC than that of IDC in the overall cohort. Different therapeutic approaches from luminal IDC are essential for a better prognosis of luminal ILC.

Phase II trial of biweekly administration with eribulin after three cycles of induction therapy in hormone receptor-positive, HER2-negative metastatic breast cancer (JACCRO BC-03).

PURPOSE: Metastatic breast cancer (MBC) is usually incurable; treatment aims to maximize patients' function and quality of life (QOL). Eribulin is a standard treatment in patients with MBC pretreated with anthracycline and taxane; however, the best administration schedule is unknown. METHODS: In this prospective phase II trial of patients with luminal MBC, we administered biweekly eribulin to patients who completed a three-cycle induction treatment. RESULTS: Sixty patients with hormone-receptor-positive and HER2-negative MBC were enrolled; 40 obtained stable disease (SD) or better efficacy after induction therapy, after which they were switched to biweekly maintenance administration. The median progression-free survival (PFS) in patients who switched to maintenance therapy was 15.21 weeks (95% CI 9.71-22.14), starting on the first day of maintenance therapy. Overall survival (OS) in patients who switched to maintenance therapy was 21.39 months (95% CI 18.89-32.89). PFS and OS in the whole population starting from the registration date were 19.00 weeks (95% CI 17.00-25.00) and 21.52 months (95% CI 16.23-24.25), respectively. PFS from the enrollment date for patients who received maintenance therapy was 25.29 weeks (95% CI 19.14-32.14). Patients who achieved complete response or partial response during induction therapy had significantly longer PFS compared to patients with SD. CONCLUSION: The efficacy of biweekly administration of eribulin at maintenance was nonsignificant. However, less frequent visits are convenient, and reduced dose intensity improves safety. Biweekly administration, besides dose reduction, could be an acceptable option for patients who are unable to maintain a standard regimen.

A risk-based subgroup analysis of the effect of adjuvant S-1 in estrogen receptor-positive, HER2-negative early breast cancer.

PURPOSE: The Phase III POTENT trial demonstrated the efficacy of adding S-1 to adjuvant endocrine therapy for estrogen receptor-positive, HER2-negative early breast cancer. We investigated the efficacy of S-1 across different recurrence risk subgroups. METHODS: This was a post-hoc exploratory analysis of the POTENT trial. Patients in the endocrine-therapy-only arm were divided into three groups based on composite risk values calculated from multiple prognostic factors. The effects of S-1 were estimated using the Cox model in each risk group. The treatment effects of S-1 in patients meeting the eligibility criteria of the monarchE trial were also estimated. RESULTS: A total of 1,897 patients were divided into three groups: group 1 (≤ lower quartile of the composite values) (N = 677), group 2 (interquartile range) (N = 767), and group 3 (> upper quartile) (N = 453). The addition of S-1 to endocrine therapy resulted in 49% (HR: 0.51, 95% CI: 0.33-0.78) and 29% (HR: 0.71, 95% CI 0.49-1.02) reductions in invasive disease-free survival (iDFS) events in groups 2 and 3, respectively. We could not identify any benefit from the addition of S-1 in group 1. The addition of S-1 showed an improvement in iDFS in patients with one to three positive nodes meeting the monarchE cohort 1 criteria (N = 290) (HR: 0.47, 95% CI: 0.29-0.74). CONCLUSIONS: The benefit of adding adjuvant S-1 was particularly marked in group 2. Further investigations are warranted to explore the optimal usage of adjuvant S-1.

An exploratory study for tuft cells in the breast and their relevance in triple-negative breast cancer: the possible relationship of SOX9.

BACKGROUND: Breast cancer is highly heterogeneous, suggesting that small but relevant subsets have been under-recognized. Rare and mainly triple-negative breast cancers (TNBCs) were recently found to exhibit tuft cell-like expression profiles, including POU2F3, the tuft cell master regulator. In addition, immunohistochemistry (IHC) has identified POU2F3-positive cells in the normal human breast, suggesting the presence of tuft cells in this organ. METHODS: Here, we (i) reviewed previously identified POU2F3-positive invasive breast cancers (n = 4) for POU2F3 expression in intraductal cancer components, (ii) investigated a new cohort of invasive breast cancers (n = 1853) by POU2F3-IHC, (iii) explored POU2F3-expressing cells in non-neoplastic breast tissues obtained from women with or without BRCA1 mutations (n = 15), and (iv) reanalyzed publicly available single-cell RNA sequencing (scRNA-seq) data from normal breast cells. RESULTS: Two TNBCs of the four previously reported invasive POU2F3-positive breast cancers contained POU2F3-positive ductal carcinoma in situ (DCIS). In the new cohort of invasive breast cancers, IHC revealed four POU2F3-positive cases, two of which were triple-negative, one luminal-type, and one triple-positive. In addition, another new POU2F3-positive tumor with a triple-negative phenotype was found in daily practice. All non-neoplastic breast tissues contained POU2F3-positive cells, irrespective of BRCA1 status. The scRNA-seq reanalysis confirmed POU2F3-expressing epithelial cells (3.3% of all epithelial cells) and the 17% that co-expressed the other two tuft cell-related markers (SOX9/AVIL or SOX9/GFI1B), which suggested they were bona fide tuft cells. Of note, SOX9 is also known as the "master regulator" of TNBCs. CONCLUSIONS: POU2F3 expression defines small subsets in various breast cancer subtypes, which can be accompanied by DCIS. The mechanistic relationship between POU2F3 and SOX9 in the breast warrants further analysis to enhance our understanding of normal breast physiology and to clarify the significance of the tuft cell-like phenotype for TNBCs.

Radiotherapy versus low-dose tamoxifen following breast-conserving surgery for low-risk and estrogen receptor-positive breast ductal carcinoma in situ: an international open-label randomized non-inferiority trial (TBCC-ARO DCIS Trial).

BACKGROUND: Radiotherapy (RT) following breast-conserving surgery (BCS) is mainly used to decrease the rate of ipsilateral breast tumor recurrence (IBTR) in women with breast ductal carcinoma in situ (DCIS). Recent studies have demonstrated that low-dose tamoxifen significantly reduces IBTR in breast DCIS. Here, we aim to determine whether the administration of low-dose tamoxifen is non-inferior to RT in preventing IBTR in patients with low-risk characteristics of breast DCIS. METHODS/DESIGN: This is a prospective, international, open-label, randomized, non-inferiority trial. Patients with low-risk clinicopathologic features (> 40 years old, low risk of breast cancer susceptibility gene (BRCA) 1 and BRCA2 mutations, mammographically detected unicentric and non-mass lesions, low- or intermediate-grade without comedo or necrosis, measuring < 2.5 cm with margins ≥ 3 mm, and estrogen receptor-positive status) of DCIS who underwent BCS will be randomized at a 1:1 ratio to either receive tamoxifen (5 mg/day) for 5 years or undergo RT with conventional fractions (50 Gy in 25 fractions) or hypofractionations (40.05 Gy in 15 fractions). Randomization will be stratified by the Taiwan Breast Cancer Consortium. As approximately 5% of patients cannot tolerate the side effects of low-dose tamoxifen and will receive RT, we estimate that 405 patients will be randomized to a low-dose tamoxifen arm and 405 patients to the RT arm, according to a non-inferiority margin within 5% of IBTR difference and 90% ß-power noticing non-inferiority. The primary endpoints are breast tumor recurrence, including ipsilateral, regional, contralateral, and distant recurrence of breast DCIS or invasive cancer. The secondary endpoints are overall survival and adverse effects of RT and tamoxifen. Translational studies will also be conducted for this trial. DISCUSSION: This is the first non-inferiority trial on breast DCIS. This study will provide an important recommendation for clinical physicians on whether to use low-dose adjuvant tamoxifen for patients with low-risk breast DCIS who do not want to receive adjuvant RT. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT04046159, Registered on April 30, 2019.